1. Field of the Invention
The present invention relates to processing color photographic materials, and, in particular, to a color photographic process which effectively promotes the color developing speed without increasing the formation of fog and further improves the stability of the color developer.
2. Description of the Prior Art
In color photographic processing, a color photographic material comprising a support having coated thereon silver halide photographic emulsions containing or not containing cyan, yellow and magenta couplers is image-wise exposed and then subjected to a series of processings for forming images as dye images.
The fundamental steps of color photographic processing are a color development step and a silver removal step. That is, in the color development step, the exposed silver halide in the silver halide color photographic material oxidizes a color developing agent and at the same time is reduced to silver, and, further, the oxidized color developing agent undergoes a coupling reaction with any couplers present to give dye images. The color photographic material thus developed is then processed in a silver removal step in which the developed silver formed in the color development step is oxidized by the action of an oxidizing agent (called a "bleaching agent") and the oxidized silver is dissolved away from the photographic material by a complexing agent for silver ion (called a "fixing agent"). Thus, the photographic material processed has formed thereon only dye images.
In a practical development process, the process further includes auxiliary steps for retaining photographic and physical qualities of the color images and to improve the stability or preservability of color images, in addition to the above-mentioned two fundamental steps of color development and silver removal. For example, there are usually employed a hardening bath for preventing light-sensitive emulsion layers being excessively softened during processing, a stop bath to effectively stop the development reaction, a stabilization bath to stabilize the color images formed, and a bath for removing a backing layer from the support of the color photographic material. Such a kind of color photographic process has been conventionally practiced since 1940.
As a photographic process other than the above-mentioned processing system, a color intensification process is sometimes employed and such a process is described in detail in, for example, U.S. Pat. No. 3,674,490; and in Japanese Patent Applications Laid Open (OPI) 9728/'73 and 9729/'73.
It is further known that an amine compound or an alcohol can be incorporated in a developer for promoting development speed. Examples of such known amine compounds are, for example, alkylamines as described in U.S. Pat. No. 2,196,037, aralkylamines as described in U.S. Pat. Nos. 2,496,903; 2,515,147; and 2,541,889, phenoxyalkylamines as described in U.S. Pat. No. 2,482,546, heterocyclic alkylamines as described in U.S. Pat. No. 2,608,183, morpholine, piperidine, etc., as described in U.S. Pat. No. 2,304,025, and xylylenediamines as described in U.S. Pat. No. 1,086,618. Also, examples of alcohols used for this purpose are aralkyl alcohols as described in U.S. Pat. No. 2,304,925.
However, while the above-mentioned amines may promote development speed to some extent in color development, the formation of fog increases with increases in development speed. Moreover, when a color developer containing such an amine is used after being stored for a long period of time, it causes fog and color mixing, or, further, the color developer is accompanied by the formation of coloring and precipitates.
When an aralkyl alcohol is incorporated in a color developer, the development speed may be promoted to some extent, but since an aralkyl alcohol has essentially low solubility in water, when a color developer containing an aralkyl alcohol is allowed to stand, oil drops form therein. It is known to use glycols as an auxiliary solvent for preventing the formation of such oil drops in the color developer, but the use of such glycols insufficiently improves the solubility of aralkyl alcohols in water.
Recently, the concentration of color developers used has tended to be higher, and, with increased requirements for using such highly concentrated color developers, the technique of keeping such highly concentrated color developers stable becomes more and more important. On the other hand, however, in the case of using an aralkyl alcohol, it is difficult to employ the same for practical purposes in a highly concentrated color developer for the reasons stated above.